Hevac1,
Listening in mono is an excellent idea also!
The mike placement during recording of solo piano pieces varies greatly from recording to recording it seems and is often done for enhancement of stereo effect at cost perhaps of a more natural presentation as one might hear located within optimal listening distance of several feet of the piano. Stereo may not offer much other than an unnatural perspective in this case. If so, who needs it.
Maybe this is part of why other genres sound real enough but solo piano doesn't?
If your pre-amp has mono switching, try that...it's easy
Also, most recordings have compressed dynamics to some extent compared to live. Adding and properly applying a dynamic range enhancement device like say a dbx 3bx series 3 or 4bx will make a diffence in recordings where the dynamics just ain't there to start with.